Zhang Yu, Yang Liwen, Li Yange, Tang Shiyu, Zhang Yiqingqing, Sun Pinzhi, Lu Hao
College of Veterinary Medicine, Northwest A&F University, Xianyang, Shaanxi, China.
Front Microbiol. 2025 Aug 25;16:1641192. doi: 10.3389/fmicb.2025.1641192. eCollection 2025.
Locoism refers to a neurological disorder in livestock caused by chronic ingestion of locoweeds, which contain toxic alkaloid swainsonine produced by the fungus . Therefore, reducing swainsonine levels not only prevents locoism but may also transform these toxic plants into animal feed. In this study, we identified a pivotal role for the gene in swainsonine biosynthesis. Using siRNA-mediated gene silencing, we demonstrated that knockdown of markedly reduced swainsonine accumulation in fungal mycelia. Transcriptomic and metabolomic analyses revealed that silencing triggered broad metabolic reprogramming, notably impacting aromatic amino acid metabolism, carbon metabolism, and antioxidative pathways, and underscoring its central role in fungal growth and secondary metabolism. Furthermore, we screened and inoculated a hypovirulent strain suitable for co-cultivation with peeled seed embryos of , and the symbiont showed significantly reduced level of swainsonine without negatively impacting plant growth. These findings provide a promising strategy for mitigating locoism by engineering endophytic fungi with attenuated toxicity.
疯草病是指家畜因长期摄入疯草而引发的一种神经紊乱疾病，疯草含有由真菌产生的有毒生物碱苦马豆素。因此，降低苦马豆素水平不仅能预防疯草病，还可能将这些有毒植物转化为动物饲料。在本研究中，我们确定了该基因在苦马豆素生物合成中的关键作用。通过小干扰RNA介导的基因沉默，我们证明敲低该基因可显著降低真菌菌丝体中苦马豆素的积累。转录组学和代谢组学分析表明，该基因沉默引发了广泛的代谢重编程，尤其影响芳香族氨基酸代谢、碳代谢和抗氧化途径，并突出了其在真菌生长和次级代谢中的核心作用。此外，我们筛选并接种了一种适合与去壳种子胚共培养的低毒力菌株，共生体显示苦马豆素水平显著降低，且对植物生长没有负面影响。这些发现为通过改造毒性减弱的内生真菌来减轻疯草病提供了一种有前景的策略。
